CN115372412B - Characteristic measurement method for turbine blade based on six-point positioning - Google Patents
Characteristic measurement method for turbine blade based on six-point positioning Download PDFInfo
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Abstract
The invention discloses a characteristic measurement method of a turbine blade based on six-point positioning, which is applied to the field of information processing; the technical problem to be solved is turbine blade measurement, and the technical scheme adopted is a characteristic measurement method based on six-point positioning, which comprises the following steps that (S1) six thermal imaging cameras are arranged at the bottom, the upwind high-pressure side and the downwind high-pressure side of a turbine blade based on six-point positioning; (S2) carrying out outdoor acquisition on the turbine blade by a thermal imaging technology, and acquiring six original turbine blade thermal images by six thermal imaging cameras; (S3) carrying out data preprocessing by adopting an improved deep learning algorithm to obtain a first-time processing turbine blade thermal image; (S4) adopting a region guidance algorithm for threshold judgment to establish a characteristic judgment condition function to perform characteristic judgment on the thermal image of the primary processing turbine blade to obtain characteristic parameters of the turbine blade; the invention can measure the damage condition of the turbine blade from a plurality of point positions and complete the measurement work with high precision.
Description
Technical Field
The invention belongs to the field of information processing, and more particularly relates to a characteristic measurement method of a turbine blade based on six-point positioning.
Background
Due to the large size, large surface area, and complex shape of wind turbine blades, it is difficult to perform non-destructive inspection of the same, even within a manufacturing or maintenance facility. Visual inspection does not identify defects below the surface of the wind turbine blade skin, typically made of fiberglass material. Active thermal imaging detection techniques using heat are effective for near-surface defects, but can produce false positives and false negatives due to variations in material thickness and surface emissivity. Shear deformation mapping may be used to detect fiber waves in spar caps and other areas of the blade during thermal stress or deflection testing of the blade at the factory, but this technique is slow, costly, and is typically only performed when a known problem is suspected. The horn ultrasound technique is slow and may not work with a thick carbon fiber pebble cap. Thus, the blades are typically mounted on a tower and put into service, potentially presenting manufacturing defects.
Conventional survey inspectors use aerial cranes or rope walkways, which are expensive and time consuming, and place personnel in a very hazardous working environment. Blade and tower crawlers with non-destructive inspection sensors for field inspection have been developed and tested in the prior art, but they can be very expensive, slow to operate, require repair and maintenance, suffer from complex logistics, are insensitive to defects, are poorly repeatable, and do not allow accurate measurement of defect size, area or location. Accordingly, there is a need for a fast, cost-effective, non-destructive inspection system and method for wind turbine blades to detect potential and propagated damage early enough to allow for repair on the tower before the wind turbine blade needs to be removed from the tower and repaired off site or replaced with a new blade.
Disclosure of Invention
Aiming at the problems, the invention discloses a characteristic measurement method of a turbine blade based on six-point positioning, which adopts a movable thermal imaging camera to collect images and can measure characteristic parameters of the turbine blade.
In order to realize the technical effects, the invention adopts the following technical scheme:
a feature measurement method for a turbine blade based on six-point positioning comprises the following steps:
(S1) a user observes the surrounding environment of the wind turbine generator, and six thermal imaging cameras are arranged according to the bottom of a turbine blade, the upwind high-pressure side and the downwind high-pressure side;
(S2) the thermal imaging cameras are used for carrying out outdoor collection on the turbine blades through a thermal imaging technology, and six thermal imaging cameras are used for collecting six original turbine blade thermal images;
(S3) inputting and collecting original turbine blade thermal images and performing data preprocessing by adopting an improved deep learning algorithm to obtain a primary processed turbine blade thermal image;
and (S4) receiving the thermal image of the primary processing turbine blade by the computer processing center, and establishing a characteristic judgment condition function by adopting a threshold judgment region guide algorithm to perform characteristic judgment on the thermal image of the primary processing turbine blade to obtain the characteristic parameters of the turbine blade.
As a further technical solution of the present invention, the six thermal imaging cameras adopt a six-point positioning method, which includes: placing a first thermal imaging camera and a second thermal imaging camera thirty meters on the front side and the rear side of the bottom of the turbine blade; assuming that a line passing through the first thermal imaging camera and the second thermal imaging camera is taken as a vertical line, the vertical line translates sixty meters west out to be the leeward high pressure side of the turbine blade, and the two thermal imaging cameras on the leeward high pressure side obtained by translation are taken as a third thermal imaging camera and a fourth thermal imaging camera; the vertical line translates sixty meters to the east to form the upwind high-pressure side of the turbine blade, and the two thermal imaging cameras on the upwind high-pressure side obtained by translation are a fifth thermal imaging camera and a sixth thermal imaging camera; six thermal imaging cameras are positioned at six points on the periphery of the turbine blade, and outdoor collection is carried out on the turbine blade;
as a further aspect of the invention, the first and second thermal imaging cameras are positioned to receive low levels of thermal radiation from the turbine blades; the low level of thermal radiation is due to the thermoelasticity of the stress on the turbine blade material from the gravity force of the turbine's rotational motion from the blade, and defects from mechanical stress appear in the image produced by the thermal imaging camera due to internal friction of the turbine blade and plasticity around the defect.
As a further aspect of the invention, the third and fourth thermal imaging cameras are positioned to receive a good view of the leeward low pressure side surface from the turbine blade, have a relatively low rate of angular change in three to four video frames, and have thermal imaging of rapid movement angle changes and blade twist.
As a further technical scheme of the invention, the improved deep learning algorithm is adopted for data preprocessing, and a quasi-constraint function is obtained according to turbine blade thermography data, as shown in formula (1):
formula (1)In (1),Ga quasi-constraint function representing an improved deep learning algorithm,b i a number representing an improved deep learning algorithm,ia data index representing a thermal image of the turbine blade,nrepresenting a total number of turbine blade thermographic image data; in the data preprocessing, the constraint function of the improved deep learning algorithm can effectively screen the usability of the turbine blade thermographic data, but for the turbine blade thermographic data with larger discrete difference, the tangent function tanh is needed (x) The calculation is performed as shown in equation (2):
in the formula (2), the reaction mixture is,xthe method comprises the steps of' representing discretization turbine blade thermography data, obtaining tangent relation of the discretization turbine blade thermography data through data index transformation, and comparing the discretization data with 1 through transformation to finish primary screening of the turbine blade thermography data; performing critical calculation on the sample data after screening to obtain a critical function of turbine blade thermography data as shown in formula (3):
in the formula (3), the reaction mixture is,
representing turbine blade thermographic image data threshold functions,
represents the rate at which the critical function curve grows; the critical function is similar to the tangent function of discrete data, both of which are exponential operations on the independent variable, and both of which are compared to the number 1 to derive a once-processed turbine blade thermography.
As a further technical solution of the present invention, the region guidance algorithm for threshold determination includes:
(S41) the region guiding algorithm for threshold judgment performs function conversion on the thermal image of the turbine blade in primary treatment, as shown in a formula (4):
in the formula (4), the reaction mixture is,Hshowing the thermographic algorithm standard of the once-treated turbine blade,
representing the recorded once-processed turbine blade thermographic data function,
representing the deviation of a thermal image of the turbine blade subjected to primary treatment;
(S42) regulating the recorded primary processing turbine blade thermal image data regularly to enable the primary processing turbine blade thermal image data to meet the operation standard of the region guidance algorithm for threshold judgment, and further finishing threshold judgment, as shown in a formula (5):
in the formula (5), the reaction mixture is,
showing the adjustment mode of the thermal image data of the turbine blade in primary processing,rthe region-guided algorithm representing the threshold decision programs the image variables,Ra set of real numbers is represented as,
the amount of lateral adjustment is indicated,
indicating a longitudinal adjustment amount; the adjusted thermal image of the once-processed turbine blade can be identified by a region-guided algorithm program for threshold judgment, and the region-guided algorithm program for threshold judgmentThe characteristic parameters of the turbine blade are judged by the equation (6):
in the formula (6), the reaction mixture is,Wa region-guided algorithm representing a threshold decision determines a conditional function,fshowing the coefficient of the thermal image determination condition of the primary processing turbine blade,
identifying a standard primary processing turbine blade thermal image pattern form by using an area guide algorithm representing threshold judgment;
(S43) in the neighborhood calculation of the region-guided algorithm for threshold determination, the feature parameter determination for the turbine blade whose primary processing turbine blade thermal image is similar is referred to as neighborhood determination, as shown in formula (7):
in the formula (7), the reaction mixture is,
showing the adjustment mode of the thermal image data of the secondary processing turbine blade to be detected,
a characteristic parameter function form representing a neighbor turbine blade,
indicating that the nearest neighbor algorithm identifies a standard function,
a bias-derived argument representing a standard neighbor function,
partial derivatives representing nearest neighbor functionsA variable;
(S44) the final determination of the characteristic parameter of the monitored turbine blade is determined by a mode method, and the determination result is expressed as shown in formula (8) by sample selection and neighbor comparison thereof:
in the formula (8), the reaction mixture is,
the region representing the threshold decision directs the algorithm to include characteristic parameters for the mode turbine blades,
a determination result of a characteristic parameter of the turbine blade in the region-guided algorithm of the threshold determination,jthe region indicating the threshold decision directs the algorithm to identify a range,
indicating a decision phase angle condition.
As a further technical scheme of the invention, the computer processing center transmits the characteristic parameters of the turbine blades to a display, and a user obtains the characteristic parameters of the turbine blades through the display; the user control computer processing center issues commands to the waveform generator which amplifies the command signals through the signal amplifier to drive the linear motor actuator to control the operation of the thermal imaging camera.
As a further technical scheme of the invention, the thermal imaging camera obtains an original thermal imaging image of the turbine blade by reflecting light rays from a reflector, the reflector is coupled above the periphery of the thermal imaging camera, and the distance between the thermal imaging camera and the reflector and the angle of the reflector are controlled by a linear motor actuator.
The invention has the beneficial and positive effects that:
different from the conventional technology, the method can measure the damage condition of the turbine blade from multiple points, acquire the thermal imaging image of the turbine blade through the thermal imaging technology, and then complete the measurement work with high precision through the characteristic parameters of the mode turbine blade recorded by the region guidance algorithm judged by the threshold.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive exercise, wherein:
FIG. 1 illustrates a flow chart of a six-point positioning based feature measurement method for a turbine blade;
FIG. 2 illustrates a six point positioning schematic of six thermal imaging cameras;
FIG. 3 illustrates a thermal imaging camera measurement schematic directly beneath a turbine blade;
FIG. 4 illustrates a thermal imaging camera measurement schematic located on the low pressure side of the wind below the turbine blades;
FIG. 5 illustrates a turbine blade feature measurement process map;
fig. 6 shows a comparison graph of the feature measurement accuracy of the three measurement methods.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, it being understood that the embodiments described herein are merely illustrative and explanatory of the invention, and are not restrictive thereof;
as shown in fig. 1, a feature measurement method for a turbine blade based on six-point positioning includes the steps:
(S1) a user observes the surrounding environment of the wind turbine generator, and six thermal imaging cameras are arranged according to the bottom of a turbine blade, the upwind high-pressure side and the downwind high-pressure side;
in particular embodiments, wind turbine blades are typically manufactured from a bonded composite shell forming a high pressure side and a low pressure side. The trailing edge is bonded as well as the leading edge, in some cases between two flanges formed by inner and outer glass fibre skins constituting the sandwich panel 18, to the edges of which are bonded spar webs 3.0 which may be of glass fibre or carbon fibre laminate or other similar composite material, which may be solid glass fibre laminates or sandwich structures having glass fibre or carbon fibre panels, and core materials of foam, balsa wood or other suitable material having a high compressive strength. The spar web 3.0 is bonded to the spar caps with an adhesive to form an i-beam. Sometimes there is a second or even a third spar web forming a box beam.
(S2) the thermal imaging cameras are used for carrying out outdoor collection on the turbine blades through a thermal imaging technology, and six thermal imaging cameras are used for collecting six original turbine blade thermal images;
in particular embodiments, the thermal imaging camera capturing turbine blade thermal images defects such as adhesive peel or non-bonding present at the spar cap to spar web 3.0 adhesive bond can lead to catastrophic failure of the blade in service, and fiber waves in the solid spar cap laminate can also lead to cracking and ultimately blade failure. Furthermore, cracks or splits in the trailing edge in the adhesive joints of the casing on the high and low pressure sides may be an indication of excessive bending of the blade during operation. The trailing edge adhesive bond supports blade torsional loads in the region of maximum blade chord width towards the root end. Unless detected in time and the turbine is shut down and repaired in time, cracks and breaks in the adhesive bond at these locations can also lead to blade failure. When one of the reinforcing elements (e.g. glass or carbon fibre) breaks, a noticeable sound is produced, as if the stick breaks. Sound propagates through the structure of the wind turbine blade and through the enclosed space defined by the inner surface of the blade skin. In addition, a pressure gradient is formed in the enclosed space due to centripetal acceleration. The pressure difference between the part of the enclosure near the wind turbine hub and the outermost part of the enclosure may be in the order of 2 psi.
(S3) inputting and collecting original turbine blade thermal images and performing data preprocessing by adopting an improved deep learning algorithm to obtain a primary processed turbine blade thermal image;
in a specific embodiment, the preprocessing of the image is a very important step in the digital image processing process, and the preprocessing is processing performed before performing a main task such as object recognition on the input image in the image analysis process. The main purpose of image preprocessing is to eliminate irrelevant information in an image to be detected as much as possible, recover useful real information, enhance the detectability of relevant information and simplify data to the maximum extent, so that the subsequent required image processing is performed more conveniently and rapidly, and the reliability of the result is improved. According to different requirements, image preprocessing mainly comprises denoising, contrast enhancement, gray level transformation, geometric transformation and the like. Therefore, the quality of the preprocessed image directly affects subsequent image analysis, such as classification, image segmentation, target identification and positioning and the like, and therefore a proper image preprocessing method needs to be selected before the image is positioned.
And (S4) receiving the thermal image of the turbine blade subjected to primary processing by a computer processing center, and establishing a characteristic judgment condition function by adopting a region guide algorithm for threshold judgment to perform characteristic judgment on the thermal image of the turbine blade subjected to primary processing to obtain characteristic parameters of the turbine blade.
In a specific embodiment, the feature extraction technique of the image is the first step of the image analysis process, and the edge of the image is one of the most basic features of the image. By edge, it is simply meant the set of those pixels in the image where the gray of the surrounding pixels has an abrupt change and the edge is the most obvious change of the local feature in the image. The end of one area and the beginning of another area are marked. The edge is widely existed between an object and a background, between the object and between an area and the area, so the edge detection, also called edge feature extraction, of the image is an important method for realizing image segmentation, the purpose of the edge feature extraction is to identify points with obvious gray level change in a digital image, and the pixel set forms the edge of the image. The main purpose of image edge detection is to preserve important structural characteristics of the image and remove information that is not related to edges, which also greatly reduces the amount of data.
In a specific embodiment, the six thermal imaging cameras adopt a six-point positioning method, which includes: placing a first thermal imaging camera and a second thermal imaging camera thirty meters on the front side and the rear side of the bottom of the turbine blade; assuming that a line passing through the first thermal imaging camera and the second thermal imaging camera is taken as a vertical line, the vertical line is translated sixty meters in the west direction to be a downwind high-pressure side of the turbine blade, and the two thermal imaging cameras on the downwind high-pressure side are translated to be a third thermal imaging camera and a fourth thermal imaging camera; the vertical line translates sixty meters to the east to form the upwind high-pressure side of the turbine blade, and the two thermal imaging cameras on the upwind high-pressure side obtained by translation are a fifth thermal imaging camera and a sixth thermal imaging camera; six thermal imaging cameras are positioned at six points around the perimeter of the turbine blade while outdoor acquisition of the turbine blade is performed.
In a particular embodiment, the first thermal imaging camera and the first thermal imaging camera are located at a position below the blade to receive thermal radiation from the low pressure side leading edge and the front. This position reduces angular variations due to blade rotation in the image during frame acquisition. Turbine blade thermographic images taken from a thermographic camera are recorded by a computer processing center, or as video files in a storage device in the thermographic camera, and processed and presented using peak storage or other image processing techniques, and presented on a display to obtain good image quality and quantitative measurements of size and position, comparing features of known size within a target range.
In a particular embodiment, the first and second thermal imaging cameras are positioned to receive low levels of thermal radiation from the turbine blades; the low level of thermal radiation is due to the thermoelasticity of the stress on the turbine blade material from the gravity force of the turbine's rotational motion from the blade, and defects from mechanical stress appear in the image produced by the thermal imaging camera due to internal friction of the turbine blade and plasticity around the defect.
In a particular embodiment, the third and fourth thermal imaging cameras are positioned to receive a good view of the leeward low pressure side surface from the turbine blade, with relatively low rates of angular change in three to four video frames, with thermal imaging of rapid movement angle changes and blade twist.
In particular embodiments, the turbine blade points at an angle other than horizontal, and the image is more distorted proportionally due to the varying distance of the infrared camera from the point on the blade. If the blade is facing downwards, the distance from the camera to the tip of the blade is approximately equal to half the height of the tower. The image scale at the tip of the blade will be twice the image scale value at the root of the blade, the defect measurement will be twice the actual size, and the digital thermal image or sequence of photographs can be played back frame by frame to allow the analyst to select the frame with the best image quality to define the boundary of the anomaly. An image measurement tool measuring each pixel value along a line passing through the defect indication may be programmed to measure a signal-to-noise ratio, which may be defined as the pixel value of an area adjacent to the square of the defect divided by the pixel value of the square of the defect indication. Among the many tools known to those skilled in the art of image processing, such tools can be used to quantitatively select the image with the best image quality. The site operator may image the wind turbine blades in the position segment to capture a plurality of image sequences of all three blades at least once as they pass through the camera field of view. This may be followed by a rotation of the camera on its mount to capture the next blade segment, to take a sequence of multiple images of all three blades as they pass through the camera field at least once, and so on until an image of the entire blade is captured. In other words, as the blade rotates, segments that are segmented by length along the longitudinal axis of the blade are scanned incrementally from the inside out. An analyst reviews the frame-by-frame sequence over the entire blade length, an image scale with a distance correction factor may be used to obtain accurate measurements.
In a specific embodiment, the data preprocessing is performed by using an improved deep learning algorithm, and a quasi-constraint function is obtained according to turbine blade thermographic data, as shown in formula (1):
in the formula (1)，GA quasi-constraint function representing an improved deep learning algorithm,b i a number representing an improved deep learning algorithm,ia data index representing a thermal image of the turbine blade,nrepresenting a total number of turbine blade thermographic image data; in the data preprocessing, the constraint function of the improved deep learning algorithm can effectively screen the usability of the turbine blade thermographic data, but for the turbine blade thermographic data with larger discrete difference, the tangent function tanh is needed (x) The calculation is performed as shown in equation (2):
in the formula (2), the reaction mixture is,xthe method comprises the steps that discretization turbine blade thermography data are represented, the tangent relation of the discretization turbine blade thermography data is obtained through data index transformation, and the discretization data can be compared with 1 through transformation, so that preliminary screening of the turbine blade thermography data is completed; performing critical calculation on the sample data after screening to obtain a critical function of turbine blade thermographic data as shown in formula (3):
in the formula (3), the reaction mixture is,
representing turbine blade thermographic image data threshold functions,
represents the rate at which the critical function curve grows; the critical function is similar to the tangent function of discrete data, both of which are exponential operations on the independent variable, and both of which are compared to the number 1 to derive a once-processed turbine blade thermography.
In a specific embodiment, the step of the region guidance algorithm for threshold determination includes:
(S41) the region guiding algorithm for threshold judgment performs function conversion on the thermal image of the turbine blade in primary treatment, as shown in a formula (4):
in the formula (4), the reaction mixture is,Hshowing the thermographic algorithm standard of the once-treated turbine blade,
representing the recorded once-processed turbine blade thermographic data function,
representing the deviation of a thermal image of the turbine blade recorded for primary treatment; the invention makes it possible for a wind turbine generator to select a calibration feature in the digital image that changes apparent width with distance but does not change if the viewing angle changes, thereby providing a more reliable measurement. An example of such an object is a sphere, whose diameter varies with distance but not with viewing angle, and a cylinder is another example. The root end of the wind turbine blade is cylindrical and is connected to a pitch bearing in the hub.
(S42) regulating the recorded primary processing turbine blade thermal image data regularly to enable the primary processing turbine blade thermal image data to meet the operation standard of the region guidance algorithm for threshold judgment, and further finishing threshold judgment, as shown in a formula (5):
in the formula (5), the reaction mixture is,
showing the adjustment mode of the thermal image data of the turbine blade in primary processing,rthe region-guided algorithm representing the threshold decision programs the image variables,Ra set of real numbers is represented as,
the amount of lateral adjustment is indicated,
represents the longitudinal adjustment amount;
in particular embodiments, the blade root end diameter may be used to calibrate the image scale of the wind turbine blade, regardless of the blade pitch or the perspective to the ground, and then allow other features to be measured at the same approach distance. Due to the increased thickness of the steel at the weld of the tower joints, these joints retain heat from the sun and remain visible by the infrared camera for a large part of the night, when thermal inspection of the wind turbine blades is best, as defects with thermal emissions are washed away. The adjusted thermal image of the primary processing turbine blade can be identified by a region-guided algorithm program for threshold judgment, the characteristic parameters of the turbine blade are judged in a region-guided algorithm programming mode for threshold judgment, and the judgment conditions are shown as a formula (6):
in the formula (6), the reaction mixture is,Wa region-guided algorithm representing a threshold decision determines a conditional function,fshowing the coefficient of the thermal image determination condition of the primary processing turbine blade,
identifying a standard thermal image graphic form of the turbine blade processed at one time by using an area guidance algorithm representing threshold judgment;
(S43) in the neighborhood calculation of the region-guided algorithm for threshold determination, the feature parameter determination for the turbine blade whose primary processing turbine blade thermal image is similar is referred to as neighborhood determination, as shown in formula (7):
formula (7)) In (1),
showing the adjustment mode of the thermal image data of the turbine blade to be treated,
representing a characteristic parameter functional form of a closely spaced turbine blade,
indicating that the nearest neighbor algorithm identifies a standard function,
a bias-derived argument representing a standard neighbor function,
a partial derivative dependent variable representing a neighbor function;
in particular embodiments, known dimensions at the turbine blade root or tower weld may be used to calibrate the image scale. Imaging of a region of known dimensions may be accomplished using digital thermography, photography, or any other passive or active imaging technique. The software is then used to determine the image scale in pixels/foot. The pixel count is then used to determine the dimension calibrated in pixels of the indicated size or area. This would allow the software to comparatively determine the size of other features or objects located at approximately the same distance. The size of these features or anomalies may then be converted back to a conventional size measurement, such as feet, meters, or other units of length.
(S44) the final decision on the characteristic parameters of the monitored turbine blade is determined by a mode method, and the decision result is expressed as shown in formula (8) by sample selection and neighbor comparison thereof:
in the formula (8), the reaction mixture is,
the region representing the threshold determination guides the characteristic parameters of the modal turbine blades that the algorithm incorporates,
a determination result of a characteristic parameter of the turbine blade in the region-guided algorithm of the threshold determination,jthe region indicating the threshold decision directs the algorithm to identify a range,
indicating a decision phase angle condition.
In particular embodiments, the imaging software may then integrate the dimensional measurements to determine the surface area of the feature or anomaly, and video images of the blade root end and blade hub may be continuously recorded with a camera and synchronized with video frames from a thermal imaging camera that images the blade for anomalies using at least one of GPOS timing signals, wireless signals, or other means to identify the blade serial number or rotor lifting lugs to identify the blade position of a particular blade having the anomaly or feature of interest. Such imaging may be performed with the wind turbine blades at a plurality of radial rotational angles in order to generate an image scaling template that corrects for image distortions over the field of view of the digital image as the wind turbine rotor rotates. The imaging may be performed while the wind turbine blades are rotating, so there is no need to fix the wind turbine blades or take the assembly off-line during the inspection process. For horizontally oriented blades, the arc angle contained by the defect marks on the blade in the image is relatively small, and therefore the defect size and positioning error is relatively small.
In a specific embodiment, the computer processing center transmits the turbine blade characteristic parameters to a display, and a user obtains the turbine blade characteristic parameters through the display; the user control computer processing center issues commands to the waveform generator which amplifies the command signals through the signal amplifier to drive the linear motor actuator to control the operation of the thermal imaging camera. The thermal imaging camera moves rotationally to follow the motion of the blade about the axis. The thermal imaging camera is mounted on a frame or plate and is connected to a hinge, which is also connected to a frame member that supports the actuator. The opposite end of the plate is connected to an electrical actuator by a flexible joint. Such as a hinge or universal joint. Movement of the actuator causes the thermal imaging camera to move up and down, where the movement is substantially the same when aligned with a portion of the blade, which tends to stabilize the blade in the field of view of the thermal imaging camera. Additional actuators may be operated simultaneously to move the thermal imaging camera in multiple directions, but with additional complexity. In practice, one actuator is sufficient if a clear view of when the blade reaches the horizontal position during rotation is available in the field. Another option is to rotate the entire actuator, support plate and thermal imaging camera to align the movement of the actuator with the movement of the blade during data acquisition. Reducing the drive mass reduces the vibration and power requirements of electronic and electric actuators that may be battery operated or powered by the vehicle used by the operator. The motion of the camera should be generally aligned with the direction of motion of the turbine blade in the camera's field of view during its rotation about the axis.
In a particular embodiment, the thermal imaging camera obtains a thermal image of the original turbine blades by reflecting light off of mirrors coupled over the periphery of the thermal imaging camera whose cyclic motion in the direction of blade motion can be adjusted to track the approximate motion of each blade as it rotates through the field of view. The rotation will essentially stop the rotational movement for several frames. The blade appears to hang in space, allowing time for the thermal camera to generate higher resolution images of the moving blade. The adjustment includes the magnitude of the ramp voltage, which will compensate for the blade rotational speed, the duration of the ramp function, and the time between each start of the ramp function. The output signal of the waveform generator is amplified in a signal amplifier which then drives the linear motor actuator. The movement of the mirror causes the short image sequence produced by the thermal imaging camera to be derotated. The user may choose to image all the blades by starting the tracking motion every 3 seconds, the image of the same blade will be presented and de-rotated. The spring may be used to provide a restoring force to return the mirror to its starting position ready for the next blade pass. Only one or more video frames need to be tracked, and the image blurring of the thermal imager caused by the rotation of the blade can be obviously improved. The frequency of motion of the de-rotating mirror can be calculated in the following example. Assuming that the turbine is operating at 15rpm, the thermal imaging camera has a frame rate of 30 frames per second, and it is desirable to spin up 4 video frames. The period t of the turbine is the time required for 1 revolution, in this case 4 seconds. We start moving the mirror from 0 seconds to track the blade as it enters the field of view of the thermal imaging camera. The angle of the mirror changes continuously (increases or decreases depending on the direction the blade moves in the field of view) within 0.133 seconds and then returns to the starting position. To track only one blade, the tracking motion is started every 4 seconds (t). To track all three blades in sequence, each tracking movement is started, after which the mirror returns to the starting position to wait for the next tracking cycle.
In a specific embodiment, the invention is used for carrying out experiments on the measurement work of the turbine blade, and the practicability of the characteristic measurement method adopted by the invention is verified. The laboratory uses Intel i7 9600KF to configure the computer with 32+256GB memory capacity. And (4) setting a field experiment environment, wherein the power of an experiment wind turbine is 1200W, the working voltage is 220V, the resolution of a monitoring image is 2600 x 1200ppi, the analysis precision of the equipment image is more than 90%, and the analysis speed of field data is more than 8.0MB/s. Compared with a system for measuring the turbine blade based on an unmanned aerial vehicle (scheme one) and a system for measuring the turbine blade based on a wireless sensor network (scheme two) in the prior art, the invention adopts three measuring methods to collect turbine blade image data for 24 hours, and calculates the percentage of invalid images in all images as a measuring precision result by image recognition and characteristic extraction through a background server, as shown in table 1:
TABLE 1 turbine blade measurement accuracy results
The comparison experiment was further completed by the comparison results in table 1, and the feature measurement accuracy pairs of the three measurement methods were obtained according to the simulation software as shown in fig. 6: as can be seen from FIG. 6, the measurement accuracy of the invention is attenuated with the change of the running time, and the minimum value is 97.683%; the first scheme has larger reduction amplitude along with the change of time, and the minimum measurement precision is 94.448%; the second scheme is similar to the first scheme, and the measurement precision is continuously reduced along with the extension of the running time, and the minimum value is 93.672%. In conclusion, the method has obvious effect on the measurement work of the turbine blade, and shows the superiority of the region guidance algorithm for threshold judgment.
Although specific embodiments of the present invention have been described above, it will be understood by those skilled in the art that these specific embodiments are merely illustrative and that various omissions, substitutions and changes in the form and details of the methods and systems described above may be made by those skilled in the art without departing from the spirit and scope of the invention; for example, it is within the scope of the present invention to combine the steps of the above-described methods to perform substantially the same function in substantially the same way to achieve substantially the same result; accordingly, the scope of the invention is to be limited only by the following claims.
Claims (6)
1. A feature measurement method based on six-point positioning for a turbine blade comprises the following steps:
(S1) a user observes the surrounding environment of the wind turbine generator, and six thermal imaging cameras are arranged according to the bottom of a turbine blade, the upwind high-pressure side and the downwind high-pressure side;
(S2) the thermal imaging cameras are used for carrying out outdoor collection on the turbine blades through a thermal imaging technology, and six thermal imaging cameras are used for collecting six original turbine blade thermal images;
(S3) inputting and collecting original turbine blade thermal images and performing data preprocessing by adopting an improved deep learning algorithm to obtain a primary processed turbine blade thermal image;
(S4) receiving the thermal image of the turbine blade subjected to primary processing by a computer processing center, and establishing a characteristic judgment condition function by adopting a region guidance algorithm for threshold judgment to perform characteristic judgment on the thermal image of the turbine blade subjected to primary processing to obtain characteristic parameters of the turbine blade;
the method comprises the following steps of performing data preprocessing by adopting an improved deep learning algorithm, and obtaining a quasi-constraint function according to turbine blade thermal image data, wherein the quasi-constraint function is shown in a formula (1):
in the formula (1), the reaction mixture is,Ga quasi-constraint function representing an improved deep learning algorithm,b i a number representing an improved deep learning algorithm,ia data index representing a thermal image of the turbine blade,nrepresenting a total number of turbine blade thermographic image data;
in the data preprocessing, the constraint function of the improved deep learning algorithm can effectively screen the usability of the turbine blade thermographic data, but for the turbine blade thermographic data with larger discrete difference, the tangent function tanh is needed (x) The calculation is performed as shown in equation (2):
in the formula (2), the reaction mixture is,xthe method comprises the steps of' representing discretization turbine blade thermography data, obtaining tangent relation of the discretization turbine blade thermography data through data index transformation, and comparing the discretization data with 1 through transformation to finish primary screening of the turbine blade thermography data;
performing critical calculation on the sample data after screening to obtain a critical function of turbine blade thermography data as shown in formula (3):
in the formula (3), the reaction mixture is,s(x') represents turbine blade thermographic image data threshold functions,ηrepresents the rate at which the critical function curve grows; tangent function of critical function and discrete dataSimilarly, both are exponential operations on independent variables, both of which are compared with the number 1 to obtain a first-time processed turbine blade thermography;
the region guidance algorithm for threshold judgment comprises the following steps:
(S41) performing function conversion on the thermal image of the turbine blade processed at the first time by using a region guiding algorithm for threshold judgment, wherein the function conversion is shown in a formula (4):
in the formula (4), the reaction mixture is,Hshowing the thermographic algorithm standard of the once-processed turbine blade,
representing the recorded once-processed turbine blade thermographic data function,
representing the deviation of a thermal image of the turbine blade recorded for primary treatment;
(S42) regulating the recorded primary processing turbine blade thermal image data regularly to enable the primary processing turbine blade thermal image data to meet the operation standard of the region guidance algorithm for threshold judgment, and further finishing threshold judgment, as shown in a formula (5):
in the formula (5), the reaction mixture is,
showing the adjustment mode of the thermal image data of the turbine blade in primary processing,rthe region-guided algorithm representing the threshold decision programs the image variables,Ra set of real numbers is represented as,
the amount of lateral adjustment is indicated,
represents the longitudinal adjustment amount; the adjusted thermal image of the primary processing turbine blade can be identified by a region-guided algorithm program for threshold judgment, the characteristic parameters of the turbine blade are judged in a region-guided algorithm programming mode for threshold judgment, and the judgment conditions are shown as a formula (6):
in the formula (6), the reaction mixture is,Wa region-guided algorithm representing a threshold decision determines a conditional function,fshowing the coefficient of the thermal image determination condition of the primary processing turbine blade,θidentifying a standard primary processing turbine blade thermal image pattern form by using an area guide algorithm representing threshold judgment;
(S43) in the neighborhood calculation of the region-directed algorithm for threshold determination, the feature parameter determination for a turbine blade whose first-order processing turbine blade thermal image is close is expressed as a neighborhood determination, as shown in equation (7):
in the formula (7), the reaction mixture is,
showing the adjustment mode of the thermal image data of the turbine blade to be treated,
representing a characteristic parameter functional form of a closely spaced turbine blade,θ(x,y) Indicating that the nearest neighbor algorithm identifies a standard function,
self-variation of partial derivatives representing standard neighbor functionsThe amount of the compound (A) is,
a partial derivative dependent variable representing a neighbor function;
(S44) the final determination of the characteristic parameter of the monitored turbine blade is determined by a mode method, and the determination result is expressed as shown in formula (8) by sample selection and neighbor comparison thereof:
in the formula (8), the reaction mixture is,
the region representing the threshold decision directs the algorithm to include characteristic parameters for the mode turbine blades,
a determination result of a characteristic parameter of the turbine blade in the region-guided algorithm of the threshold determination,jthe region indicating the threshold decision directs the algorithm to identify a range,
indicating a decision phase angle condition.
2. The method of claim 1, wherein the method comprises: the six thermal imaging cameras adopt a six-point positioning method;
the method comprises the following steps: placing a first thermal imaging camera and a second thermal imaging camera thirty meters on the front side and the rear side of the bottom of the turbine blade;
assuming that a line passing through the first thermal imaging camera and the second thermal imaging camera is taken as a vertical line, the vertical line translates sixty meters west out to be the leeward high pressure side of the turbine blade, and the two thermal imaging cameras on the leeward high pressure side obtained by translation are taken as a third thermal imaging camera and a fourth thermal imaging camera;
the vertical line translates sixty meters to the east to form the upwind high-pressure side of the turbine blade, and the two thermal imaging cameras on the upwind high-pressure side obtained by translation are a fifth thermal imaging camera and a sixth thermal imaging camera;
six thermal imaging cameras are positioned at six points around the perimeter of the turbine blade while outdoor acquisition of the turbine blade is performed.
3. The method of claim 2, wherein the method comprises:
the first and second thermal imaging cameras positioned to receive low level thermal radiation from the turbine blade;
the low level of thermal radiation is due to the thermoelasticity of the stress on the turbine blade material from the gravitational force of the rotating motion of the blades.
4. The method of claim 2, wherein the method comprises: the third thermal imaging camera and the fourth thermal imaging camera are positioned to receive a good view of the leeward low pressure side surface from the turbine blade with a relatively low rate of angular change in three to four video frames.
5. The method of claim 1, wherein the method comprises: the computer processing center transmits the characteristic parameters of the turbine blades to a display, and a user obtains the characteristic parameters of the turbine blades through the display; the user control computer processing center issues commands to the waveform generator which amplifies the command signals through the signal amplifier to drive the linear motor actuator to control the operation of the thermal imaging camera.
6. The method of claim 1, wherein the method comprises: the thermal imaging camera obtains an original thermal imaging image of the turbine blade through reflected light rays of a reflector, the reflector is coupled above the periphery of the thermal imaging camera, and the distance between the thermal imaging camera and the reflector and the angle of the reflector are controlled through a linear motor actuator.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105469054A (en) * | 2015-11-25 | 2016-04-06 | 天津光电高斯通信工程技术股份有限公司 | Model construction method of normal behaviors and detection method of abnormal behaviors |
| CN110082355A (en) * | 2019-04-08 | 2019-08-02 | 安徽驭风风电设备有限公司 | A kind of wind electricity blade detection system |
| CN111060057A (en) * | 2019-12-25 | 2020-04-24 | 贵阳航发精密铸造有限公司 | Turbine blade profile measuring method based on three-coordinate measuring machine |
| CN211950751U (en) * | 2019-11-21 | 2020-11-17 | 东莞深圳清华大学研究院创新中心 | Fan blade detection device |
| CN115015270A (en) * | 2022-05-25 | 2022-09-06 | 中国民航大学 | Near-surface defect on-wing detection method for aero-engine component based on hot air infrared |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105469054A (en) * | 2015-11-25 | 2016-04-06 | 天津光电高斯通信工程技术股份有限公司 | Model construction method of normal behaviors and detection method of abnormal behaviors |
| CN110082355A (en) * | 2019-04-08 | 2019-08-02 | 安徽驭风风电设备有限公司 | A kind of wind electricity blade detection system |
| CN211950751U (en) * | 2019-11-21 | 2020-11-17 | 东莞深圳清华大学研究院创新中心 | Fan blade detection device |
| CN111060057A (en) * | 2019-12-25 | 2020-04-24 | 贵阳航发精密铸造有限公司 | Turbine blade profile measuring method based on three-coordinate measuring machine |
| CN115015270A (en) * | 2022-05-25 | 2022-09-06 | 中国民航大学 | Near-surface defect on-wing detection method for aero-engine component based on hot air infrared |
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